Other than defeating people in story mode 5 times, here are the ways to unlock the rest of the single duel opponents: anything under 1000 are LV1 duelists, anything above 1300 are LV 3 duelists, anything in between are LV 2

Other than defeating tag teams in story mode 5 and 10 times, here are the ways to unlock the rest of the tag duel opponents: anything under 1000 are LV1 duelists, anything above 1390 are LV 3 duelists, anything in between are LV 2. Note: for the Summon requirements, for it to count it has to appear in the Duel Result to count (For example, the game won't detect Rainbow Dark Dragon when summoned using Rainbow Gravity)